Last lathe



w. SLACK Nov. 19, 1929.

LAST LATHE 2 Sheets-Sheet 1 Filed Oct. 29, 1927 PE/v TUAL J15 Nov. 19, 1929. w. w. SLACK I 1, ,278

LAST LATHE Filed Oct. 29, 1927f Z-Shts-Sheet 2 Patented Nov. 19, 1929 o sir res pus orr cr.

WALTER/W. sLAcK, or SPRINGFIELD, VERMONT, AssieNoRi'To' FITZ EM IP IREjD OUB IJE PIVOT LAST COMPANY, or AUBURNQMAINE, AcoR-ron'ATIoN OFfMAINE P m w LATHE Application filed October- 29, 1927. Serial No."229,'736.

This, invention relates to copyingladies and is disclosed as embodied in alathe for-cut ting lasts. vSuch lathes comprise a swing frame in which a model and'a last block are rotated against a model wheel and cutter mounted in the machine.- The model acts as a spacerbetween the model wheel and the" swing frame, pushing out the frame when its high points come in contact with the model 16 Wheel, and letting it fall back at the low;

points thus.regulatingthe depth of-cut inthe block. The ordinary swing frame is heavy and possessed of considerable inertia.

As the leading-side of the cone, for example, of a last "model rollsover themodel wheel the swing frame is forced-sharply outward and its inertia tends to keepit moving after frame causes it to twist, allowing the block 'to;fall too far toward; the cutter, which then cuts'too deep into the block. Conversely as} the model wheel rollsinto a-hollow on the model there is a tendencyto jar at the bot-I,

tom, where the direction of relative move-. 'soiment between thewheel'c'enterand the model center changes.

It is an object offthe the model "whee1,by virtue of "an increased or additional restoring force applied to the swing frame as it is; pushed out the model wheel, thus overcoming the tendency of the model toleave the model wheel,jand"'vice versa.

, In accordance with the present invention f have provided a flexible tension memberfforapplying the additional'res'toring force to'the swing frame, and a movable abutment over which it runs. Preferably the movable abut ment is moved bya connection to the swing 1 frame so as to increase the restoring force as the swing frame moves outwardly, thus holding themodel-against the modelwheelas and 7 Fig. 3 is a more extensive view showing the H swingframe in its inoperative latched-out popresent invention" to provide a machinein which the model shall! be held steadily and firmly in contact with ;thewheelgrolls up andover ahigh point of the-model.

*Inthe drawings l Fig. 1 is aside elevation of those partsf of 2 a last lathe necessary to an understanding of,

the present-invention,'-showingthe swing 7 frame on center, that is, with the axis of the V model onthe face of the model wheel; I

Flg. 2 IS a similar view showing the swing frame at the outermost point of its swing;

sition.

The swing frame 10 is pivotedat12and has the well-known, link 14 at each end pivoted to a'cra-nk 16 on the ordinary rocker shaft 18.

The frame is pulled toward the zero -posi- .tion shown in Fig. 1' in which the axis 19 of the'model is on the face 21 of the model wheel by a cord 20' operated by a-weight 22, and

connected to the bottom of the swing'frame at 24. 'The cord 20-passjes over afixed pulley 26, and also over a'pulley-28 on a-stub shaft 30- mounted in one of several holes 32 in" one arm of a bell crank 34 pivotedat 36 on the machine frame. A link 38, adjustable in length, connects the other arm of the bell crank to the bottom of the swing frame.

Regarding for the moment the 'pulley28 as Y fixed it is obvious that as the-swing frame is forced out from the Fig. 1 position to that of Fig. 2,-the'cord 20 will lift the weight, 22 and the tension in the cord will be proportional to the acceleration necessary to lift the weight.

- The upward movement of the weight is determinedby the shape of the model, as is also the downward movement if the model rotates very slowly. Now the maximum accelerati'on of the weight occurs very close to the bottom of a depression'out of which the model wheel is rolling, and the acceleration becomes negative, zero or very small considerably before the top of'the hill is reached. Thereforethe' 'c'ord will slacken at the top of the hill and the swin frame, out of control, will 'bound'awa y' rom the model wheel, causing the faulty cutting described above.

Consider now the. situation as shown in the drawing. As the swlng frame moves out- I so Patent of the UnitedflStatesis cord to the-sw-ing frame, thereby providing the additional pull necessary to hold the model against the model wheel steadi ly. as the.

time-cycleof this operation'ofacourseis the The effect produced may be regulated by moving the stub shaft from one toanother I of the holes 32, and by changing th'elen'gth of the'link 38 which controlsthe range of roetation-of the=bell crank 34," since the; cycle of the effect produced depends on the orienta tion of the'bell crank.

tensioned by-the' weight. 22,I=-regard it; as

gs within the scope of: my invention to use a SPIHIO' or other means for this purpose, or to x I. .i use anelastlc cord. J 7' i I-Iavlng thus described 'my'inven-tioin what I claim as new and desire to secure by Letters -1. In a copying lathefa swing frame, a flexible 1361151011 member having oneend fastened-to the sw ng frame and arrangedto pull the swing frame toward zeroaposi-tion, V as a movable 'abutmentover wlnch the tension 7 member hangs, 1 and means for altering the 1 7 effective position of theabutment to vary the restoring force on the swing frame during.

each swing of theframe, V p v 2". In a copying lathe, a swing2 fra'me, a flexible tension membenliaving ;one1/.end fastened to the swing frame, and:a weight on its other end, arranged to .pull the swing: frame toward zero pos tion, a movable abut- '45Qment over which the tension memberxhangs,

and means for altering the effective position ofthe abutment to-vary the restoring force" ontheswing frame during each swing of the frame. 7 In a copyinglathe', a swing frame,-a

flexible tension mei1'1ber fhaving' one. end

fastenedfto the'swing frame 'andarranged to.

, pull'the swing frame toward Zero position, a

' {met ablelabutment over wliich the' tension hangs for altel mg the 6f 1 means, connecting the abutment to the swing frame for moving the abutment continuously in the direction opposite to the movement of 7 the swing frame, as the swing. frame'moves; 11. In a copying lathera swing'frame,"a

99 11196 M H fective position the abutment as'the swing f-KamemQYGS y le winger eine, r e assthat'of theswing frame movement.

fastened to the swing frameyand a .weight on itsother end, arranged topull theswing:

frame toward zeroposition amovable abut- Thus additional acceleration is wheel rollspver the high point of the model ,i The effect is reversed as the model wheel rolls down into a hollow on the model, the force diminishing until the bottom is reached. The

same as that of the swing frame movement.

. J y In copying lathe, aswing frame, a flexible atension member; one; end;

5. In a copying lathe, a swing frame, a

flexible tension member having one end" fastened to the swing frame, means for creatmg tension in the tension member arranged to pull the swing frame toward zero pOSltlOIl, a

movable abutment over which the tension.

member hangs, and means, connecting the abutment to the swingfframe for, moving the abutment as the swing frame moves,"

a copying lathe, a swing frame, a flexible tension member having one end fastened totheswing frame, and a weight on its other end, arranged to pull theswing frame toward zero-position, a movable abutment over' which'the tension member hangs, and.v I

means connecting the abutment to the swing frame for moving the abutment as the swing frame moves. 2

7 In a'copying lathe,-aswing frame, a 1 i flexible tension' member having one end fas While Ihave herein shown the cord 20 as tened to the swing frame, and a weight on its other end, arranged to pull the swing frame toward zero position,ga movable abut ment over'wh ch the tension member hangs,

andmeans for moving the abutm'ent in the direction opposite-to the movement of the swing frame, as the swing frame moves.

8."-In a -co'py1ng lathe, a swlngfram a flexible tens1onmember-hav1ng one end-fas tened t'othe swing frame and arranged to pull the swing frame" toward zero position, 1 a 'movable; abutment over which the tension.

member I. hangs, and means connecting the movement of the swing frame' moves.

9. In a copyinglathda swing frame, a

-fleXible tension memberhaving one-end'fas tened to the swing frame, and a weight on its other end, arranged to pullth'e swing frame toward zero position, movable abutment over which the tension member hangsyf and means connecting the abutment totheswing frame :for moving the abutmentin the direction opposite to the movement of v the swing frame, as theswing'frame moves. i I

10. In a copying lathe, azswing frame, a, flexible tension; member having one end fas-- tenedto the swing frame, and a weight on its other end arranged to pull the swing frame toward a Zero position, a movable abutment over which the tension member hangs, and

flexible tension member having one end fas other end arranged to pull the 'swingfra-me tened to the swing fram and a weight on'its mounted on the lever to move therewith, over which the tension member hangs, and means for moving the lever as the swing frame moves. a

13. In a copying lathe, a swing frame, a flexible tension member having one end fastened to the swing frame and a weight on its I other end arranged to pull the swing frame toward zero position, a lever, v a pulley mounted on the lever to move therewith, over which the tension member hangs, and means connecting the lever to the swing frame for moving the lever as the swing frame ifioves.

14. In a copying lathe, a swing frame, a flexible tension member having one end fastened to the swing frame and a weight on its other end arranged to pull the swing frame toward zero position, a bell crank, a pulley mounted on one arm of the bell crank over which the tension member hangs, and a link connecting the other arm of the bell crank to the swing frame.

15. In a copying lathe, a swing frame, a flexible tension member having one end fastened to the swing frame and a weight on its other end arranged to pull the swing frame toward zero position, a bell crank, a pulley adjustably mounted on one arm of the bell crank over which the tension member hangs, and a link connecting the other arm of the bell crank to the swing frame.

16. In a copying lathe, a swing frame, a flexible tension member having one end fastened to the swing frame and arranged to pull the swing frame toward zero position, a bell crank, a pulley adjustably mounted on one arm of the bell crank over which the tension member hangs, and a link adjustable in length connecting the other arm of the bell crank to the swing frame.

17 In a copying lathe, a swing frame, a" flexible tension member having one end fastened to the swing frame, and a Weight on its other end, arranged to pull the swing frame toward zero position, a bell crank, a pulley adjnstably mounted on one arm of the bell crank over which the tension member hangs, and a link adjustable in length connecting the other arm of the bell crank to the swing frame.

In testimony whereof I have signed my name to this specification.

WALTER W. SLACK. 

